In recent years, with the rapid development of science and technology and the improvement of living standards, cars also occupy an increasingly important position in people's lives, and the users pay more and more attention to the acoustic environment in the car. Today, the car is often filled with a variety of sounds, such as music, navigation voices, telephone sounds, warning sounds and the like. Usually different people in the car want to listen to different voices, such as the driver wants to listen to navigation voices and warning sounds, the passengers seating in the back seats may want to listen to music. In some home theater applications there are also problems that the users of different areas want to listen to different sounds, or due to that the hearing thresholds are different, different users want to hear sounds of different volumes. In museums and other exhibition areas, the sounds of exhibits should not interfere with each other, that is, only sounds related to different exhibits can appear in front of related exhibits, thereby enhancing the user experience feelings. Similarly, the restaurant also needs to play different background music in different areas to meet different hobbies of customers. In the above scenarios, the existing sound system cannot generate independent sound sources in different areas, and cannot meet the needs of users. Although wearing earphones can solve the problem of mutual interference of sounds in respective regions, wearing earphones for a long time will not only cause the user to feel fatigue, but also damage hearing of the user.
A multi-zone sound reproduction system adjusts amplitudes and phases of input signals via a speaker array, and produces respective independent sound sources in multiple regions, creates personalized listening space for users, and avoids feeling of fatigue brought by wearing earphones. One control method commonly used in multi-zone sound reproduction systems is the sound energy contrast control method. The sound energy contrast control methods are divided into two major categories: frequency domain design and time domain design. The frequency domain sound energy contrast control method in the prior art cannot guarantee the causality of the time-domain impulse response filter signals, and hence the contrast performance at the non-control frequency point may decrease. The time domain sound energy contrast control method in the prior art directly avoid non-causal problems of the time-domain impulse response filter signals in the time-domain design, and hence the decreasing of the contrast performance at the non-control frequency point in frequency domain sound energy contrast control method can be solved. However, the time-domain sound energy contrast control method in the prior art does not take the errors in speaker frequency responses into account, which is far from the actual.
The problems of the time-domain sound energy contrast control method in the prior art will reduce the contrast performance of the multi-zone sound reproduction system, enlarge the mutual interference between the sound fields of respective regions, cannot create a personalized private listening space for each user, and will reduce the possibility of mass production of real systems. Aiming at the problem of contrast performance decrease introduced by speaker frequency response errors in the existing sound energy contrast control method, it is necessary to find a more simple and effective method to overcome the contrast performance decrease introduced by the speaker frequency response errors.